Miscellaneous

snapshot.debian.org

The snapshot archive is a wayback machine that allows access to old
packages based on dates and version numbers. It consists of all
past and current packages the Debian archive provides.

The ability to install packages and view source code from any given date can be
very helpful to developers and users. It provides a valuable resource for
tracking down when regressions were introduced, or for providing a specific
environment that a particular application may require to run. The snapshot
archive is accessible like any normal apt repository, allowing it to be easily
used by all.

Usage

In order to browse snapshots of the archives kept on snapshot.debian.org, simply
follow the links on the top left. They will lead you to a list of months for
which data was imported, and the list entries in turn will point you to all
timestamps of a given month's snapshots.

To learn which snapshots exist, i.e. which date strings are valid, simply
browse the list as mentioned above. Valid date formats are
yyyymmddThhmmssZ or simply yyyymmdd. If there
is no import at the exact time you specified you will get the latest
available timestamp which is before the time you specified.

To access snapshots of suites using Valid-Until that are older than a dozen days,
it is necessary to ignore the Valid-Until header within Release files, in order
to prevent apt from disregarding snapshot entries ("Release file expired"). Use
aptitude -o Acquire::Check-Valid-Until=false update or
apt-get -o Acquire::Check-Valid-Until=false update for this purpose.

If you use at least apt version 1.1.exp9 (stretch and later), you can use this instead:

If you want anything related to a specific package simply enter the
source package name in the form, or find it in the package index.

News

2014-06-01

We added a cluster of machines generously provided by LeaseWeb to provide the snapshot.debian.org
service.

Snapshot used to run on two machines hosted at and provided by the Wellcome Trust Sanger Institute and by the
Electrical and Computer Engineering
department at the University of British Columbia, Canada. A few months ago,
the machine at UBC, named stabile.debian.org, started to die.
Since it was approaching its storage capacity limits anyway, we began looking
for a new second home for snapshot, and LeaseWeb offered! Providing snapshot
from two different places (now Sanger and LeaseWeb) allows us to survive
temporary and not-so-temporary issues that affect any single site.

Currently, snapshot consists of 24 terabytes of data in about 15 million files,
and it appears to be growing at a rate of approximately 5 terabytes a year (or
about 10 megabytes per minute).

2012-09-23

Just a quick datapoint: Currently snapshot has about 11 million files in a bit
over 16 terabytes of data.

2010-12-14

Around 2010-11-20 the server which hosted snapshot-master stumbled into
hardware issues. This did not affect the external storage but only the front-end
server. Since the master was down no new data was imported into the snapshot
system and the remaining mirror kept presenting its data as of the 20th.

Fortunately the people at the Wellcome Trust
Sanger Institute, which hosts snapshot-master, have been able to give us
a replacement machine quite quickly. Thanks!

While the master was down, snapshot information was collected by a non-public
backup system. This data has been integrated into snapshot.debian.org.
Unfortunately, one of the package pools, debian-ports, was not
archived on that secondary system, and for this archive we have no data
in the affected time period.

2010-09-07

Renamed the backports.org archive to debian-backports as it has now
moved
to debian.org infrastructure. A rewrite rule has been put in place
so old URLs should continue to work (at least for HTTP clients that know
how to follow HTTP redirects).

2010-08-16

Set up a caching proxy in front of the two snapshot webservers. This will help
in cases where an entire organisation uses various apt sources.list entries on
a lot of their machines.

Usually such entities would use proxy caches like squid and then there is no
problem, assuming the cache works correctly. Unfortunately apt-cacher, apparently
a common choice which is supposed to be smarter for debian archives, completely ignores the
Cache-Control headers that snapshot sends and hits this service for all
requests made to anything under dist/. A single apt-get
update can cause up to a few dozen of such requests and when multiplied
by scores of machines - all running the update at the same time - this caused
the snapshot backend to run into limits. Now such requests won't hit the backend
any more.